The book that created a rift between President Trump and his former campaign chief executive and adviser Steve Bannon hit the shelves Friday morning, ahead of the original Tuesday release date, despite the president's threat to block its publication.

Michael Wolff, author of Fire and Fury: Inside The Trump White House, told NPR's Kelly McEvers that he "100 percent" stands behind his reporting, which the White House and some of the book's subjects have sharply criticized.

"I am not a hit man," Wolff said. "I'm someone who just found his way into this story of our time and just wanted to tell it as clearly as possible and with as much understanding as possible."

The first part of the interview is set to air on All Things Considered on Friday afternoon.

The pushback and legal threats from the White House may have made the book even more popular. Wolff's workwent on sale at midnight in at least one Washington, D.C., bookstore and reportedly sold out in less than 20 minutes. It had already reached No. 1 on Amazon's best-seller list.

Wolff's book paints a portrait of a White House in disarray, with an incompetent Trump at the center.

"I think the two fundamental issues were that Donald Trump doesn't read anything. Let me accent that — anything. Nothing," Wolff told NPR. "If you're working for the president of the United States, that's an odd position because how do you get information to him? That's already a major hurdle. But then there's the second hurdle — that not only does he not read; he doesn't listen. So it becomes from Day 1, the crisis of the presidency: You can't tell him anything."

For example, Wolff pointed to how Trump was obsessed on his first full day in office with claiming that the crowds at his inauguration had been larger than at former President Barack Obama's — which was inaccurate. However, Wolff said, "You couldn't say to him, 'That's not true. You shouldn't have said it from the beginning, but now we have to fix it.' He wouldn't read it, and you couldn't tell him it because he won't listen to you. It is entirely his reality."

Wolff also describes how Trump's decision to surround himself with competing viewpoints was doomed to fail. These range from his daughter Ivanka Trump and son-in-law, Jared Kushner, who held more liberal positions, to chief of staff Reince Priebus, who was a mainstream Republican, to chief strategist Steve Bannon, who represented the far right.

"Each are trying to use their particular leverage and each has leverage with the president. Also, in order to increase their leverage with the president, they were trying to kill each other. In some nearly literal sense, kill each other," Wolff said. "Certainly, Jared Kushner believed that Steve Bannon was leaking — that the information about Kushner's relationship and conversations with Russians, which put him in legal peril, was coming from Bannon. Reince Priebus almost every day of this administration was a guy who was going to be fired the next day."

"This was an organization that was almost, I'd say, in a real sense shattered from the first day," Wolff said.

Wolff detailed the unprecedented access he was given, describing how he "sat there, day after day, and talked to whoever was willing to talk to me and was a fly on the wall — or as Nora Ephron used to say, a wallflower at the orgy."

"When you write a book like this, people regret what they said to me," Wolff said. "What they say to any reporter who they relax with and they forget who they're talking to, I have sympathy for that, and I think the natural response is to say, 'Oh my God, I didn't say it.' But I will tell you, they said it."

He says he entered the reporting process with an open mind and was "willing to think that this unusual figure had a new way to approach things" that just might work. "I feel that that is not the case now, and I saw and learned that everyone around him feels that is not the case. The train will hit the wall."

While Wolff's book is supposed to be about Trump, comments made by now-former top aide Bannon have captured much of the media attention this week.

The book quotes Bannon describing a June 2016 meeting at Trump Tower involving Donald Trump Jr., other Trump campaign aides and Russians as "treasonous" and "unpatriotic."

Since excerpts of the book first appeared in New York magazine and The Guardian ran a reportearlier this week, the president has been on the attack, saying Bannon has "lost his mind."

On Thursday night, in a tweet, Trump said he authorized "zero access to White House (actually turned him down many times) for author of phony book!" and added that he "never spoke to him for book." Trump went on: "Look at this guy's past and watch what happens to him and Sloppy Steve [Bannon]!"

Trump and the White House have also tried to downplay the influence Bannon had on Trump's win — something Wolff says is undeniable.

"Steve Bannon is responsible for Donald Trump's election. When Steve joined the campaign in August, they were finished — even Trump acknowledged they were finished," Wolff said. But Bannon helped Trump lay up an economics-focused populist message that resonated with many disaffected voters in states like Michigan and Wisconsin that would be decisive in the outcome.

As for the access he was given to the president, Wolff told NPR that he spent about three hours in totalwith Trump during the campaign and after his inauguration. A description of the reporting process posted by New York magazine says Wolff conducted more than 200 interviews overall, including with "most members of his senior staff, and many people to whom they in turn spoke."

White House press secretary Sarah Huckabee Sanders said Wednesday that Trump spoke with Wolff only once since taking office and that it was a brief phone conversation, not a sit-down interview. She said most of the interviews Wolff did at the White House were at Bannon's request.

The fallout from the book does seem to have damaged Bannon's credibility with some former supporters, including Rebekah Mercer, the billionaire backer of Bannon's website Breitbart News. Mercer issued a statement to The Washington Post on Thursday, saying, "My family and I have not communicated with Steve Bannon in many months and have provided no financial support to his political agenda, nor do we support his recent actions and statements" — a development that Trump pointed to in a tweet on Friday.

But Wolff predicted we haven't seen the last of Bannon.

"I think he has many acts left in him," Wolff said. "I would put my money on Steve Bannon right now instead of Donald Trump."

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ROBERT SIEGEL, HOST:

A storm hit Washington this week. Its name is "Fire And Fury: Inside The Trump White House," a new book by journalist Michael Wolff. The reporting in the book about the first 200 days of Donald Trump's presidency has set off a series of recriminations, denials and controversy that has dominated every news cycle since excerpts of the book leaked earlier this week. Our colleague Kelly McEvers spoke to Michael Wolff today.

KELLY MCEVERS, HOST:

One of the immediate fallouts of "Fire And Fury" has been a very public break between President Trump and his onetime chief strategist Steve Bannon. Shortly after the first excerpts of the book were published, President Trump issued a statement saying, Steve Bannon has nothing to do with me or my presidency. When he was fired, he not only lost his job; he lost his mind. And in an effort to stop publication of the book, the president's lawyer sent a cease and desist letter to Henry Holt, the publisher of the book, and to the book's author, Michael Wolff, who is with me now. Welcome.

MICHAEL WOLFF: Thank you.

MCEVERS: So I just want to start right off with that cease and desist letter. It says in part that there are numerous false or baseless statements in this book. And so I just want to ask you; do you stand by every single word in it?

WOLFF: One hundred percent.

MCEVERS: We have heard, you know, a spokesperson for the White House, Sarah Huckabee Sanders - said there are numerous false things in there. Thomas Barrack, who's a friend of the president, who you quote in the book calling President Trump stupid and crazy, told The New York Times he never said that. Katie Walsh, who was deputy chief of staff last year, is also challenging a quote in the book. So what do you say to these specific claims about how they were characterized in your book?

WOLFF: You know, when you write a book like this - and I wrote this over a long period of time and spoke to people over a long period of time - people regret what they said to me, what they say to any reporter who they relax with and they forget who they're talking to. And I have sympathy for that. And I think the natural response is to say, oh, my God, I didn't say it. But I will tell you they said it.

MCEVERS: Let's talk about the book itself. For the many people who still haven't read it, you write a lot about President Trump and his personality in particular, you know, talking about things like how he lacks the ability to take in third-party information and about how he's more interested in immediate gratification than sort of a longer-term game of, you know, laying down policies the way other presidents have done. How much time did you spend with the president himself?

WOLFF: You know, let me just - I just want to say something 'cause it's an interesting thing that's starting to happen...

MCEVERS: Sure.

WOLFF: ...Which I'm becoming the poster boy for taking down Donald Trump. That certainly has never been my intention. My intention was to go into the White House and to report what I saw and what I heard. I thought that from the beginning, this was going to be an extraordinary story in whatever way it went. And I had no no way of knowing what way it would go. So it was not really so much about who - my analysis of Donald Trump but the people who were closest to him, the people who had to run this White House, the people who became this White House.

MCEVERS: But just - I do need to ask the question. How much time did you spend with the president himself?

WOLFF: I have spent about three hours with the president over the course of the campaign and in the White House.

MCEVERS: One thing that you write about that has been said before but not in as much detail as you give here is that the people around Donald Trump and even Trump himself did not expect him to win the election. What was the plan if he lost?

WOLFF: I think everyone would have been vastly happier if he had lost. Donald Trump would have been the most famous man in the world. His family would have gone from mere local socialites to major international figures. Steve Bannon would have effectively run the Tea Party. It would have been great for everybody.

MCEVERS: You know, after the win, yes, people were surprised. But they're in the White House. They've got a job to do. You know, it seems like you're constantly asking this question about, like, why people are working with him. In the beginning, you say it's because they believe there's just some kind of magic - right? - like, some unique astuteness and cunning because he won - right? - 'cause he won this election. There must be some there there.

WOLFF: Let me point another curious wrinkle that none of the people who went to work for Trump in the White House knew him very well. What they know basically is that he has been elected president of the United States. And they thought, OK, it's a new day, a new kind of president, a new page. Let's make the best of this.

MCEVERS: Right and just my sense from the book is that over time, though, that this idea that there must be some magic there, there must be some there there starts to wear off. What did they learn about him?

WOLFF: I think the two fundamental issues were that Donald Trump doesn't read anything. And let me accent that - anything, nothing. And that's - if you're working for the president of the United States, that's an odd position because how do you get information to him? And that's already a major hurdle. But then there's the second hurdle that not only does he not read. He doesn't listen. So it becomes from day one the crisis of the presidency. You can't tell him anything.

So on the first day of the presidency when he announces that the inaugural crowds were three or four or five times larger than they actually were, you couldn't say to him - you couldn't give him the information to say, that's not true. And you couldn't tell him it because he wouldn't listen to you. It is entirely his reality.

MCEVERS: So because - so working there becomes the job of how to manage a person like this.

WOLFF: And people began to learn sort of strategies. I mean, a central strategy is that, you know, he's obsessively focused on the media. So whatever you told him had to be processed through the media, which set up this whole pattern of leaks in this White House. And then you had to have your sources. So you know, the president has this whole coterie of billionaires he speaks to at night. And so you had to plant information with them to then pass to the president. It got to be a very complicated and shortly dysfunctional situation.

MCEVERS: I think questions about Trump's competence might be one of the most chilling things about the book. You write, a hundred percent of the people around him - senior advisers, family members - every single one of them questioned his intelligence and fitness for office - just want to make sure you still stand by that, yeah?

WOLFF: Absolutely. And that's - that is the story of this book. Again, these people and largely good people - in a sense, all good people - came into this White House with the best of intentions. And since, you know - and I was there. This is the story that I saw. I saw the transformation. I mean, in the beginning, they, you know, pumped you full of how great Donald Trump was. And as the days went on, you saw that - the transformation, their own doubts beginning. They began to - sort of this kind of physical reaction. They would tell you these positive things, but their eyes would roll, and their - and they would kind of pantomime in certain ways. You know, they wanted to communicate to people outside that they knew, that they understood something.

And then this got more intense until you would get to the point where people were really saying, you know - really questioning him. Is he actually stupid? Is he actually illiterate? Is he - you know, what is going on - trying to understand what they were dealing with and then, in the end, getting to the point - and this was certainly most vividly expressed in the book by Steve Bannon - of just not believing that this would in any way, shape or form have a happy ending.

MCEVERS: You know, let me put that question to you. Is it just that he's not intelligent and not fit, as you write, or is there something deeper here, something more?

WOLFF: Well, I think that's already pretty deep. But yes, and then there is - and then I think what you're getting at - and certainly it's an open discussion in the White House. As Steve Bannon put it, is he losing it? And you know, one of the things that's most concerning to a lot of people around the president is this level of repetition that he has. When you speak to him, it's - you know, it's unavoidable.

And so, I mean, a lot of the people have pointed out and I think I point out in the book that there was this - you know, in the beginning, you know, he would tell the three - the same three stories within 25 minutes. And when I say tell them the same three stories, I mean with the same words and the same facial expressions. And then people found that that was shortening. So you got those three stories in the first 15 minutes. And in the first 10 minutes, you got three stories.

And so by September, actually there was a "60 Minutes" interview which they canceled, and they canceled because they worried that he couldn't do it. And they took a Fox interview, a Hannity interview instead knowing that it would be, A, friendly and with the suggestion which I believe to be absolutely true that the show supplied them with the questions beforehand.

MCEVERS: Where do you think this goes? How does this end up?

WOLFF: You know, I think in many ways, from the beginning, this has felt like like a train wreck. And as it happened, the train just kept going on, but the wall was still out there. Eventually it would hit that wall. You know, I think - and I was certainly willing to be convinced differently, willing to think that this unusual figure had a new way to approach things. And you know, what the heck, maybe it would work. I think I feel that that is not the case now. And I saw and learned and - that everyone around him feels that's not the case. The train will hit the wall.

MCEVERS: Michael Wolff, thank you so much for your time today.

WOLFF: Thank you.

MCEVERS: That's author Michael Wolff talking about his new book "Fire And Fury: Inside The Trump White House." And on Monday, you can hear more of our conversation about former chief strategist Steve Bannon. Transcript provided by NPR, Copyright NPR.